Answer :
Let a be the first term and d be the common difference.
Given: a8 = 0
To prove: a38 = 3 × a18
Now, Consider a8 = 0
⇒ a + (8 - 1)d = 0
⇒ a + 7d = 0
⇒ a = - 7d ……. (1)
Consider a38 = a + (38 - 1)d
⇒ a38 = - 7d + 37d (from equation (1))
⇒ a38 = 30d ………. (2)
Now, consider a18 = a + (18 - 1)d
⇒ a18 = - 7d + 17d (from equation (1))
⇒ a18 = 10d ……….(3)
From equation (2) and (3), we get,
a38 = 3 × a18
Hence, proved.
Rate this question :
How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Arithmetic Progression- Don't miss these Questions56 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Expertsview all courses
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation